A Long Term Evolution (LTE) wireless network includes an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) (also sometimes referred to simply as the “radio access network” or “RAN”) and an Evolved Packet Core (EPC) network (also sometime referred to simply as the “core network”).
The E-UTRAN comprises a set of base stations that wirelessly communicate with user equipment (such as smartphones) using licensed radio frequency spectrum. Each base station is also generally referred to as an “eNodeB” or “eNB.”
One type of eNodeB is a “macro” eNodeB (or eNodeB macro cell), which is a higher-power base station that is typically used to provide base station capacity in a relatively large area that includes both outdoor areas and indoor areas. In general, each location within a service provider's network is notionally within the coverage area of at least one macro eNodeB. However, in practice, there are some locations (for example, within homes and office buildings) for which good coverage cannot be provided by any macro eNodeB in an operator's network. Also, there may be some locations (for example, within public venues such as office buildings, stadiums, airports, etc.) where a large number of users congregate during certain periods. During those periods, the associated macro eNodeBs may not be able provide sufficient base-station capacity to the congregated users, even if it is possible to provide sufficient wireless coverage.
One type of eNodeB is a “small cell” or “femtocell,” which is a lower-power base station. A small cell can be used to provide improved wireless coverage and/or capacity in order to address the issues noted in the previous paragraph. This is done by deploying the small cell directly with the location that has a coverage and/or capacity issue.
Each eNodeB communicates with entities in the core network (such as, a Serving Gateway (S-GW) and a Mobility Management Entity (MME)) using the “Si interface” defined by the 3rd Generation Partnership Project (3GPP). Each eNB also communicates with other eNBs using the “X2 interface” defined by the 3GPP. These protocols are Internet Protocol (IP) based and often use public networks such as the Internet. The communication link that couples an eNodeB to the core network is referred as the “back haul” link.
Such a back haul link can be implemented using a wired connection. The back haul link can also be implemented using a wireless connection. Indeed, in some small cell deployments, the wireless back haul for a small cell eNodeB is provided using a wireless communication link that is implemented with a macro eNodeB. That is, for such a small cell eNodeB, a wireless modem, or backhaul wireless modem, is provided with the small cell that functions as user equipment from the perspective of the macro eNodeB and that functions as the termination point of an IP connection from the perspective of the small cell eNodeB.
In some cases where this type of wireless backhaul is used with a small cell, the small cell and corresponding backhaul wireless modem are proximate and may operate in the same band using time division duplexing (TDD). However, transmissions by the transmitter of one transceiver in either the small cell or the backhaul wireless backhaul modem may desensitize the receiver of the other transceiver in either the backhaul wireless modem or the small cell, respectively, due to saturation of the receiver caused by the relatively high incident power from the nearby transmitter, and an increased noise floor due to noise, e.g. sideband noise, broadcast by the transmitter.